| 摘要 |
PURPOSE:To improve the resonance frequency of a diaphragm better than a conventional diaphragm and to reproduce good sound, by fixing a part of a diameter B being 0.5-0.8 time the diameter A of the diaphragm made of a magnetic substance thin film. CONSTITUTION:A torus shaped projection to fix the diaphragm 1 is provided to the surface of the diaphragm side of a magnet 2. This projection can be a part of the magnet 2 and it can be inserted between the magnet 2 and the diaphragm 1 as a separate component. The diameter of the torus projection is 0.5-0.8 time that of the diaphragm. Further, a case 6 at the front side of the diaphragm 1 is provided with a projection arranged in the torus form having the same diameter as that on the magnet 2. The diaphragm 1 is inserted with the projections of the magnet 2 and the case 6 for fixing. Sound waves produced at the outer side from the fixed section of the diaphragm 1 pass through the projection of the case 6 and comes to an ear through an ear piece 7. |
